I am still confused. I have quadruple checked the .conf files, rechecked to step to create a virtual domain and still I get 404 when trying to access the second page of html.
1. Which URL do you see in your browser bar exactly?
2. What messages do you see in access.log and error.log in /var/log/apache2/ ?
The instructions I had said allow web ports through the firewall. It specifically said ufw which my system does not have. Is there another firewall that might be running on my Debian 11 / Apache2 system?
Firewall has nothing to do with 404 in most cases: it either blocks traffic or permits it and it doesn't change error codes.
You either do not have a firewall at all or have nftables or iptables (you can check its state with ``iptables -L -v -n``). But again: this is not a firewall problem.